Homework01 finished

.vscode/launch.json

@@ -4,6 +4,41 @@
     // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
     "version": "0.2.0",
     "configurations": [
+        {
+            "type": "java",
+            "name": "CodeLens (Launch) - test",
+            "request": "launch",
+            "mainClass": "Homework.test",
+            "projectName": "H212_87e1e728"
+        },
+        {
+            "type": "java",
+            "name": "CodeLens (Launch) - Homework01",
+            "request": "launch",
+            "mainClass": "Homework.Homework01",
+            "projectName": "H212_87e1e728"
+        },
+        {
+            "type": "java",
+            "name": "CodeLens (Launch) - BottomUpFibonacci",
+            "request": "launch",
+            "mainClass": "PrincetonJava.CodeSamples.BottomUpFibonacci",
+            "projectName": "H212_87e1e728"
+        },
+        {
+            "type": "java",
+            "name": "CodeLens (Launch) - TopDownFibonacci",
+            "request": "launch",
+            "mainClass": "PrincetonJava.CodeSamples.TopDownFibonacci",
+            "projectName": "H212_87e1e728"
+        },
+        {
+            "type": "java",
+            "name": "CodeLens (Launch) - Quadratic",
+            "request": "launch",
+            "mainClass": "PrincetonJava.CodeSamples.Quadratic",
+            "projectName": "H212_87e1e728"
+        },
         {
             "type": "java",
             "name": "CodeLens (Launch) - runRutabega",

Homework/Homework01.java

@@ -1,10 +1,36 @@
 package Homework;
-import java.util.Dictionary;
-
+import java.math.BigInteger;
+import java.util.*;
 
 public class Homework01 {
-    Dictionary d = new Dictionary();
-    public static int fib(int n) {
+
+    private static BigInteger x = new BigInteger("1");
+    public static void main(String[] args) {
+        // Scanner for terminal number input 
+        // Scanner scan = new Scanner(System.in);
+        // System.out.println("Enter # for Fibonacci Computation: ");
+        // int number = scan.nextInt();
+        // System.out.println("Fibonacci of " + number + ": " + fib(number));
+
+        // Fixed variable for debugging
+        // String number = "34";
+
+        // Command Line Argument input
+        String number = args[0];
+        int n = Integer.parseInt(number);
+        System.out.println(fib(n));
+
+    }
+    public static BigInteger fib(int index){
+        if (index == 0) return x;
+        else if (index == 1) return x;
+        return fibHelper(1,index,x,x);
 
     }
+    public static BigInteger fibHelper(int location, int target, BigInteger a, BigInteger b){
+        if (location == target) return b;
+        else{
+            return fibHelper(location + 1, target, b, a.add(b));
+        }
+    }
 }

PrincetonJava/CodeSamples/BottomUpFibonacci.java

@@ -0,0 +1,23 @@
+// Bottom-Up dynamic programming - Richard Bellman 1950s
+// computes solution to all subproblems,starting with simplest and gradually going further
+package PrincetonJava.CodeSamples;
+
+/**
+ * BottomUpFibonacci
+ */
+public class BottomUpFibonacci {
+
+    public static void main(String[] args) {
+        System.out.println(fibDP(34));
+    }
+
+    public static long fibDP(int n) {
+        long[] f = new long[n+1];
+        f[0] = 0;
+        f[1] = 1;
+        for (int i = 2; i <= n; i++)
+        f[i] = f[i-1] + f[i+2];
+        return f[n];
+
+    }
+}

PrincetonJava/CodeSamples/Quadratic.java

@@ -0,0 +1,18 @@
+package PrincetonJava.CodeSamples;
+
+
+/**
+ * Quadratic
+ */
+public class Quadratic {
+
+    public static void main(String[] args) {
+
+        double b = Double.parseDouble(args[0]);
+        double c = Double.parseDouble(args[1]);
+        double discriminant = b*b - 4.0*c;
+        double d = Math.sqrt(discriminant);
+        System.out.println((-b + d) / 2.0);
+        System.out.println((-b - d) / 2.0);
+    }
+}

PrincetonJava/CodeSamples/StandardInput.java

@@ -0,0 +1,13 @@
+package PrincetonJava.CodeSamples;
+import java.util.*;
+
+public class StandardInput {
+
+    public static void main(String[] args) {
+        Scanner test = new Scanner(System.in);
+        System.out.println("Enter Username: ");
+
+        String userName = test.nextLine();
+        System.out.println("Username is: " + userName);
+    }
+}

PrincetonJava/CodeSamples/TopDownFibonacci.java

@@ -0,0 +1,26 @@
+// Top-Down = memoization
+// Cache (store) values of each subproblem.
+// Uses a static variable (class/global variable)
+// Uses an array of longs
+
+package PrincetonJava.CodeSamples;
+
+/**
+ * TopDownFibonacci
+ */
+public class TopDownFibonacci {
+
+    public static void main(String[] args) {
+        System.out.println(fibMemo(80));
+    }
+
+    static long[] memo = new long[100];
+
+    public static long fibMemo(int n){
+        if (n==0) return 0;
+        if (n==1) return 1;
+        if (memo[n] == 0)
+            memo[n] = fibMemo(n-1) + fibMemo(n-2);
+        return memo[n];
+    }
+}